Using a toolbox, sulfur and amine ligands are attached to a variety of hydrophobic and hydrophilic resins, and the combinations were tested for the removal of heavy metals from a number of products, prepared by metal-catalyzed reactions. As a result, cheap combinations of silica resins and simple polyamines proved to be among the most effective metal scavengers particularly in apolar solvents such as cyclohexane. Expensive cyclic polyamines are not suitable, owing to kinetic retardation of complexation. Functionalized PEGbased polymers, originally designed for solid phase synthesis, show promising performance as metal scavengers. The results are discussed and compared to alternative approaches for purification such as salt-formation and chemical downstream transformation.
Desbutyl-benflumetol (DBB) is a novel antimalarial compound closely related to benflumetol (lumefantrine), of which it is a putative metabolite. The in vitro response of Plasmodium falciparum to DBB was studied in Mae Hong Son and Mae Sot, in northwest Thailand, in 1997 and 1998. In total, 155 fresh isolates were successfully tested using the World Health Organization standard in vitro microtest system (Mark II). The mean 50% effective concentration (EC 50 ) and 90% effective concentration of DBB were 6.36 and 31.09 nmol/liter, respectively. The comparison of the activity of DBB and benflumetol yielded a highly significant potency ratio of 4.52, corresponding to a more than four times higher efficacy of DBB. A considerable potency difference was found between isolates from Mae Hong Son and those from Mae Sot, reflecting lesser sensitivity in the area with marked resistance to mefloquine and quinine. This observation is also supported by a highly significant activity correlation with benflumetol (P < 0.001) and to a similar degree with mefloquine (P < 0.001), reflecting a close relationship of DBB with the class II aryl amino alcohol blood schizontocides. A less distinct association was also found with artemisinin, which was significant only at the EC 50 level, and there was no correlation at all with chloroquine. DBB is a promising antimalarial compound that merits further investigation in order to define its practical therapeutic potential.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.